1. Field of the Invention
The invention relates generally to electrochemical motive systems that can convert pressure differential from an electrochemical cell into work, for example move an item, such as a bladder or piston, or rotate a shaft, for an electrochemical pump apparatuses, for example.
2. Background
Electrochemical cells in which a chemical reaction is forced by adding electrical energy are called electrolytic cells. Central to the operation of any cell is the occurrence of oxidation and reduction reactions which produce or consume electrons. These reactions generally take place at electrode/solution interfaces, where the electrodes must be good electronic conductors and the solution should have high ion conductivity. In operation, a cell is connected to an external voltage source, and electric charge is transferred by electrons between the anode and the cathode through the external circuit. To complete the electric circuit, ions produced at an electrode must pass through the cell to the opposing electrode. Typically an electrolyte is provided between the electrodes for this purpose.
The simplest electrochemical cell consists of at least two electrodes and one or more electrolytes. The electrode at which the electron producing oxidation reaction occurs is the anode. The electrode at which an electron consuming reduction reaction occurs is called the cathode. The direction of the electron flow in the external circuit is always from anode to cathode. In an electrolysis reaction, it is necessary to apply electric power to the cell electrodes. The electrodes are connected through the electrical leads to an external source of electric power with the polarity being selected to induce the electrolyte anion flow to the anode and the cation flow to the cathode.
Generally speaking, the anode and cathode are comprised a substrate material, such as titanium, graphite, or the like, coated with a catalyst such as lead dioxide, platinum, palladium, or other known materials. The selection of a substrate and catalyst is determined by the particular electrode reaction.
Generally, an electrolyte is a material that conducts, ions. Fuel cells are a common electrochemical application. In fuel cells, proton exchange membranes are used as electrolytic and catalyst support for providing a reaction of hydrogen oxidation on the one side of membrane and oxygen reduction on the other side. This combination of membrane and electrodes can be called a Membrane Electrode Assembly (MEA).